#include "md5.h"

#include <windows.h>
#include <stdio.h>

#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

#define md5_step(f, w, x, y, z, data, s) \
        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

static void transform(unsigned int buf[4], unsigned int const in[16])
{
	register unsigned int a, b, c, d;

	a = buf[0];
	b = buf[1];
	c = buf[2];
	d = buf[3];

	md5_step(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
	md5_step(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
	md5_step(F1, c, d, a, b, in[2] + 0x242070db, 17);
	md5_step(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
	md5_step(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
	md5_step(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
	md5_step(F1, c, d, a, b, in[6] + 0xa8304613, 17);
	md5_step(F1, b, c, d, a, in[7] + 0xfd469501, 22);
	md5_step(F1, a, b, c, d, in[8] + 0x698098d8, 7);
	md5_step(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
	md5_step(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
	md5_step(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
	md5_step(F1, a, b, c, d, in[12] + 0x6b901122, 7);
	md5_step(F1, d, a, b, c, in[13] + 0xfd987193, 12);
	md5_step(F1, c, d, a, b, in[14] + 0xa679438e, 17);
	md5_step(F1, b, c, d, a, in[15] + 0x49b40821, 22);

	md5_step(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
	md5_step(F2, d, a, b, c, in[6] + 0xc040b340, 9);
	md5_step(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
	md5_step(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
	md5_step(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
	md5_step(F2, d, a, b, c, in[10] + 0x02441453, 9);
	md5_step(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
	md5_step(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
	md5_step(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
	md5_step(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
	md5_step(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
	md5_step(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
	md5_step(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
	md5_step(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
	md5_step(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
	md5_step(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

	md5_step(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
	md5_step(F3, d, a, b, c, in[8] + 0x8771f681, 11);
	md5_step(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
	md5_step(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
	md5_step(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
	md5_step(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
	md5_step(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
	md5_step(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
	md5_step(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
	md5_step(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
	md5_step(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
	md5_step(F3, b, c, d, a, in[6] + 0x04881d05, 23);
	md5_step(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
	md5_step(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
	md5_step(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
	md5_step(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

	md5_step(F4, a, b, c, d, in[0] + 0xf4292244, 6);
	md5_step(F4, d, a, b, c, in[7] + 0x432aff97, 10);
	md5_step(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
	md5_step(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
	md5_step(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
	md5_step(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
	md5_step(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
	md5_step(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
	md5_step(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
	md5_step(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
	md5_step(F4, c, d, a, b, in[6] + 0xa3014314, 15);
	md5_step(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
	md5_step(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
	md5_step(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
	md5_step(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
	md5_step(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

	buf[0] += a;
	buf[1] += b;
	buf[2] += c;
	buf[3] += d;
}

void utilities::md5::init(md5_context* ctx)
{
	ctx->buf[0] = 0x67452301;
	ctx->buf[1] = 0xefcdab89;
	ctx->buf[2] = 0x98badcfe;
	ctx->buf[3] = 0x10325476;

	ctx->bits[0] = 0;
	ctx->bits[1] = 0;
}

void utilities::md5::update(md5_context* ctx, unsigned char const* buf, unsigned int len)
{
	unsigned int t;

	/* Update bitcount */

	t = ctx->bits[0];
	if ((ctx->bits[0] = t + ((unsigned int)len << 3)) < t)
		ctx->bits[1]++;         /* Carry from low to high */
	ctx->bits[1] += len >> 29;

	t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */

								/* Handle any leading odd-sized chunks */

	if (t) {
		unsigned char* p = (unsigned char*)ctx->in + t;

		t = 64 - t;
		if (len < t) {
			memcpy(p, buf, len);
			return;
		}
		memcpy(p, buf, t);
		//byteReverse(ctx->in, 16);
		transform(ctx->buf, (unsigned int*)ctx->in);
		buf += t;
		len -= t;
	}
	/* Process data in 64-uint8_t chunks */

	while (len >= 64) {
		memcpy(ctx->in, buf, 64);
		//byteReverse(ctx->in, 16);
		transform(ctx->buf, (unsigned int*)ctx->in);
		buf += 64;
		len -= 64;
	}

	/* Handle any remaining bytes of data. */
	memcpy(ctx->in, buf, len);
}

void utilities::md5::final(unsigned char digest[md5_length], md5_context* ctx)
{
	unsigned count;
	unsigned char* p;

	/* Compute number of bytes mod 64 */
	count = (ctx->bits[0] >> 3) & 0x3F;

	/* Set the first char of padding to 0x80.  This is safe since there is
	always at least one uint8_t free */
	p = ctx->in + count;
	*p++ = 0x80;

	/* Bytes of padding needed to make 64 bytes */
	count = 64 - 1 - count;

	/* Pad out to 56 mod 64 */
	if (count < 8) {
		/* Two lots of padding:  Pad the first block to 64 bytes */
		memset(p, 0, count);
		//byteReverse(ctx->in, 16);
		transform(ctx->buf, (unsigned int*)ctx->in);

		/* Now fill the next block with 56 bytes */
		memset(ctx->in, 0, 56);
	}
	else {
		/* Pad block to 56 bytes */
		memset(p, 0, count - 8);
	}
	//byteReverse(ctx->in, 14);

	/* Append length in bits and transform */
	((unsigned int*)ctx->in)[14] = ctx->bits[0];
	((unsigned int*)ctx->in)[15] = ctx->bits[1];

	transform(ctx->buf, (unsigned int*)ctx->in);
	//byteReverse((unsigned char *) ctx->buf, 4);
	memcpy(digest, ctx->buf, md5_length);
	memset(ctx, 0, sizeof(ctx));        /* In case it's sensitive */
}

char* utilities::md5::print(unsigned char* hash, int hashlen)
{
	static char szReturn[64] = "";
	return szReturn;
}

unsigned int utilities::md5::pseduo_random(unsigned int nSeed)
{
	md5_context ctx;
	unsigned char digest[md5_length]; // The MD5 Hash

	memset(&ctx, 0, sizeof(ctx));

	init(&ctx);
	update(&ctx, (unsigned char*)&nSeed, sizeof(nSeed));
	final(digest, &ctx);

	return *(unsigned int*)(digest + 6);	// use 4 middle bytes for random value
}